This invention relates to a method and apparatus for replacing a defective terminator located on a backplane in a telecommunication switch without re-routing the communication traffic on the line card. Specifically, this invention allows telecommunication switch operators to attach a unique terminator on the rear side of the backplane to avoid re-routing traffic on the line card.
In a typical telecommunication office having a telecommunication switch, a backplane is connected to the switch with slots containing numerous line cards. Each of the line cards is capable of handling telecommunication traffic and acts as the interface between the telephone or trunk line and the switching modules. The line cards are located and positioned in slots on the backplane and have a terminator connected on the front side of the backplane. If the terminator is removed, all of the telecommunication traffic on that line card is dropped, causing a disruption in service. Therefore, before a backplane terminator can be replaced, the telecommunication traffic carried on the line card must first be first routed to another line card. The routing of the telecommunication traffic to another line card and re-routing the traffic back to the line card after the terminator is replaced can often take several hours. In a typical telecommunication switch, replacing a terminator on several hundred line cards could take hundreds of hours.
Terminators are sometimes replaced during preventative maintenance on the switch. In many instances, the voltage across the pins connecting the circuitry of the terminator drops to a sufficiently low level triggering an alarm on the switch. When this occurs, an alarm is generated indicating to a switch operator that a terminator is failing. However, the alarm does not indicate the defective terminator. Usually, the alarm signals the shelf having the defective terminator. Next, the switch operator manually tests the voltage drop across the pins of the terminators associated with each line card of shelf. Upon finding the terminator with the low voltage drop, the operator marks the terminator indicating the low voltage and the terminator associated with the previous line card. Because the identification of the defective terminator is not handled by the software on the switch, identification of the defective terminator is often accomplished on a trial and error basis.
Therefore, a need exists for replacing a terminator without having to re-route the telecommunication traffic to another line card. By removing the requirement for re-routing the traffic carried on a line card having a defective terminator, a significant amount of switch operator labor savings can be achieved.
This invention provides a methodology for efficiently replacing terminators on the backplane of a telecommunication switch such that the telecommunication traffic carried on the line card associated with the terminator being replaced not dropped or does not require a re-routing of the traffic to another line card by the switch operator. Using this methodology, the switch operator can save a significant amount of time when a terminator needs to be replaced due to routine maintenance or when a faulty terminator has outlived its useful life. Typically, the terminators for the line cards are located on the front side of the backplane. The telecommunication traffic carried by the line card is typically switched to protected status prior to replacing the terminator on the front side of the backplane. A terminator having a mirror image of electronic circuitry of the terminator being replaced is attached to the pins located on the rear side of the backplane. The line card is removed, and the terminator on the front side of the backplane is replaced. The line card is inserted back into the slot on the backplane, and the terminator on the rear side of the backplane is removed. The telecommunication traffic for the line card is taken off of protected mode status, and the line card resumes normal operation. This methodology allows for the replacement of a backplane terminator without a switch operator having to re-route the telecommunication traffic of the line card.